ci : only trigger release jobs for tags (#3883)

ci : only trigger release jobs for tags (#3883)

* ci : only trigger release jobs for tags

This commit removes the building of the release jobs on pushed to
master.

The motivation for this is that it can be confusing at the momement when
releasing that the push to master also triggers the release jobs but
the actual release will be skipped. With this change the release job is
only run when a tag is pushed which should result in a single Release
github actions job and make it easier to follow.

* ci : add GGML_NATIVE=OFF for ubuntu-22-gcc